Today, in the spirit of greater transparency with AdSense publishers, we???re sharing the revenue shares for our two main AdSense products ??? AdSense for content and AdSense for search.
As you may already know, AdSense is comprised of several products. The most popular are AdSense for content, which allows publishers to generate revenue from ads placed alongside web content, and AdSense for search, which allows publishers to place a custom Google search engine on their site and generate revenue from ads shown next to search results. Since AdSense for content and AdSense for search offer publishers different services, the revenue shared with publishers differs for each of these products.
AdSense for content publishers, who make up the vast majority of our AdSense publishers, earn a 68% revenue share worldwide. This means we pay 68% of the revenue that we collect from advertisers for AdSense for content ads that appear on your sites. The remaining portion that we keep reflects Google's costs for our continued investment in AdSense ??? including the development of new technologies, products and features that help maximize the earnings you generate from these ads. It also reflects the costs we incur in building products and features that enable our AdWords advertisers to serve ads on our AdSense partner sites. Since launching AdSense for content in 2003, this revenue share has never changed.
We pay our AdSense for search partners a 51% revenue share, worldwide, for the search ads that appear through their implementations. As with AdSense for content, the proportion of revenue that we keep reflects our costs, including the significant expense, research and development involved in building and enhancing our core search and AdWords technologies. The AdSense for search revenue share has remained the same since 2005, when we increased it.